1. Technical Field
The present invention relates to a device for assembling or coupling an impeller upon a driving shaft.
2. Discussion of Background
The torque delivered by motors typically is not constant, but rather varies or pulses. The variation or pulsation of the torque is accentuated if a speed controller is incorporated into the driving system, for example in driving an impeller. Such driving systems can include, for example, electric motors having frequency converters or electronic variators, or diesel motors.
The pulsating torques often give rise to resonance vibrations in various parts of the machine. For example, the impeller blades may be subjected to resonance vibrations and such vibrations may result in premature fatigue failure in one or more parts of the machine. In the past, this problem has been solved by introducing an adapted elastic or resilient coupling between the driving shaft of the motor and the impeller shaft. Such an arrangement is shown in FIG. 1 in the environment of a fan. In this arrangement, an elastic coupling shown at 20 is provided between the driving shafts 21 of the motor 22 and the fan shaft 24 which supports the fan impeller 26. The fan shaft 24 is carried by separate bearings 28, 30. Although this solution protects the fan from pulsating torques of the motor, the arrangement is expensive and involves large space requirements. As a result, such an arrangement is unsuitable for a number of applications.